1 /*- 2 * Copyright (c) 1996 by 3 * Sean Eric Fagan <sef@kithrup.com> 4 * David Nugent <davidn@blaze.net.au> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, is permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice immediately at the beginning of the file, without modification, 12 * this list of conditions, and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. This work was done expressly for inclusion into FreeBSD. Other use 17 * is permitted provided this notation is included. 18 * 4. Absolutely no warranty of function or purpose is made by the authors. 19 * 5. Modifications may be freely made to this file providing the above 20 * conditions are met. 21 * 22 * High-level routines relating to use of the user capabilities database 23 * 24 * $FreeBSD: src/lib/libutil/login_class.c,v 1.14.2.3 2002/08/06 07:07:52 ache Exp $ 25 */ 26 27 #include <stdio.h> 28 #include <stdlib.h> 29 #include <string.h> 30 #include <unistd.h> 31 #include <errno.h> 32 #include <sys/types.h> 33 #include <sys/stat.h> 34 #include <sys/time.h> 35 #include <sys/resource.h> 36 #include <fcntl.h> 37 #include <pwd.h> 38 #include <syslog.h> 39 #include <login_cap.h> 40 #include <paths.h> 41 #include <sys/rtprio.h> 42 43 44 static struct login_res { 45 const char *what; 46 rlim_t (*who)(login_cap_t *, const char *, rlim_t, rlim_t); 47 int why; 48 } resources[] = { 49 { "cputime", login_getcaptime, RLIMIT_CPU }, 50 { "filesize", login_getcapsize, RLIMIT_FSIZE }, 51 { "datasize", login_getcapsize, RLIMIT_DATA }, 52 { "stacksize", login_getcapsize, RLIMIT_STACK }, 53 { "memoryuse", login_getcapsize, RLIMIT_RSS }, 54 { "memorylocked", login_getcapsize, RLIMIT_MEMLOCK }, 55 { "maxproc", login_getcapnum, RLIMIT_NPROC }, 56 { "openfiles", login_getcapnum, RLIMIT_NOFILE }, 57 { "coredumpsize", login_getcapsize, RLIMIT_CORE }, 58 { "sbsize", login_getcapsize, RLIMIT_SBSIZE }, 59 { "vmemoryuse", login_getcapsize, RLIMIT_VMEM }, 60 { NULL, 0, 0 } 61 }; 62 63 64 void 65 setclassresources(login_cap_t *lc) 66 { 67 struct login_res *lr; 68 69 if (lc == NULL) 70 return; 71 72 for (lr = resources; lr->what != NULL; ++lr) { 73 struct rlimit rlim; 74 75 /* 76 * The login.conf file can have <limit>, <limit>-max, and 77 * <limit>-cur entries. 78 * What we do is get the current current- and maximum- limits. 79 * Then, we try to get an entry for <limit> from the capability, 80 * using the current and max limits we just got as the 81 * default/error values. 82 * *Then*, we try looking for <limit>-cur and <limit>-max, 83 * again using the appropriate values as the default/error 84 * conditions. 85 */ 86 87 if (getrlimit(lr->why, &rlim) != 0) 88 syslog(LOG_ERR, "getting %s resource limit: %m", lr->what); 89 else { 90 char name_cur[40]; 91 char name_max[40]; 92 rlim_t rcur = rlim.rlim_cur; 93 rlim_t rmax = rlim.rlim_max; 94 95 sprintf(name_cur, "%s-cur", lr->what); 96 sprintf(name_max, "%s-max", lr->what); 97 98 rcur = (*lr->who)(lc, lr->what, rcur, rcur); 99 rmax = (*lr->who)(lc, lr->what, rmax, rmax); 100 rlim.rlim_cur = (*lr->who)(lc, name_cur, rcur, rcur); 101 rlim.rlim_max = (*lr->who)(lc, name_max, rmax, rmax); 102 103 if (setrlimit(lr->why, &rlim) == -1) 104 syslog(LOG_WARNING, "set class '%s' resource limit %s: %m", lc->lc_class, lr->what); 105 } 106 } 107 } 108 109 110 111 static struct login_vars { 112 const char *tag; 113 const char *var; 114 const char *def; 115 int overwrite; 116 } pathvars[] = { 117 { "path", "PATH", NULL, 1}, 118 { "cdpath", "CDPATH", NULL, 1}, 119 { "manpath", "MANPATH", NULL, 1}, 120 { NULL, NULL, NULL, 0} 121 }, envars[] = { 122 { "lang", "LANG", NULL, 1}, 123 { "charset", "MM_CHARSET", NULL, 1}, 124 { "timezone", "TZ", NULL, 1}, 125 { "term", "TERM", NULL, 0}, 126 { NULL, NULL, NULL, 0} 127 }; 128 129 static char * 130 substvar(char * var, const struct passwd * pwd, int hlen, int pch, int nlen) 131 { 132 char *np = NULL; 133 134 if (var != NULL) { 135 int tildes = 0; 136 int dollas = 0; 137 char *p; 138 139 if (pwd != NULL) { 140 /* Count the number of ~'s in var to substitute */ 141 p = var; 142 for (p = var; (p = strchr(p, '~')) != NULL; p++) 143 ++tildes; 144 /* Count the number of $'s in var to substitute */ 145 p = var; 146 for (p = var; (p = strchr(p, '$')) != NULL; p++) 147 ++dollas; 148 } 149 150 np = malloc(strlen(var) + (dollas * nlen) 151 - dollas + (tildes * (pch+hlen)) 152 - tildes + 1); 153 154 if (np != NULL) { 155 p = strcpy(np, var); 156 157 if (pwd != NULL) { 158 /* 159 * This loop does user username and homedir substitutions 160 * for unescaped $ (username) and ~ (homedir) 161 */ 162 while (*(p += strcspn(p, "~$")) != '\0') { 163 int l = strlen(p); 164 165 if (p > np && *(p-1) == '\\') /* Escaped: */ 166 memmove(p - 1, p, l + 1); /* Slide-out the backslash */ 167 else if (*p == '~') { 168 int v = pch && *(p+1) != '/'; /* Avoid double // */ 169 memmove(p + hlen + v, p + 1, l); /* Subst homedir */ 170 memmove(p, pwd->pw_dir, hlen); 171 if (v) 172 p[hlen] = '/'; 173 p += hlen + v; 174 } 175 else /* if (*p == '$') */ { 176 memmove(p + nlen, p + 1, l); /* Subst username */ 177 memmove(p, pwd->pw_name, nlen); 178 p += nlen; 179 } 180 } 181 } 182 } 183 } 184 185 return np; 186 } 187 188 189 void 190 setclassenvironment(login_cap_t *lc, const struct passwd * pwd, int paths) 191 { 192 struct login_vars *vars = paths ? pathvars : envars; 193 int hlen = pwd ? strlen(pwd->pw_dir) : 0; 194 int nlen = pwd ? strlen(pwd->pw_name) : 0; 195 char pch = 0; 196 197 if (hlen && pwd->pw_dir[hlen-1] != '/') 198 ++pch; 199 200 while (vars->tag != NULL) { 201 char * var = paths ? login_getpath(lc, vars->tag, NULL) 202 : login_getcapstr(lc, vars->tag, NULL, NULL); 203 204 char * np = substvar(var, pwd, hlen, pch, nlen); 205 206 if (np != NULL) { 207 setenv(vars->var, np, vars->overwrite); 208 free(np); 209 } else if (vars->def != NULL) { 210 setenv(vars->var, vars->def, 0); 211 } 212 ++vars; 213 } 214 215 /* 216 * If we're not processing paths, then see if there is a setenv list by 217 * which the admin and/or user may set an arbitrary set of env vars. 218 */ 219 if (!paths) { 220 char **set_env = login_getcaplist(lc, "setenv", ","); 221 222 if (set_env != NULL) { 223 while (*set_env != NULL) { 224 char *p = strchr(*set_env, '='); 225 226 if (p != NULL) { /* Discard invalid entries */ 227 char *np; 228 229 *p++ = '\0'; 230 if ((np = substvar(p, pwd, hlen, pch, nlen)) != NULL) { 231 setenv(*set_env, np, 1); 232 free(np); 233 } 234 } 235 ++set_env; 236 } 237 } 238 } 239 } 240 241 242 /* 243 * setclasscontext() 244 * 245 * For the login class <class>, set various class context values 246 * (limits, mainly) to the values for that class. Which values are 247 * set are controlled by <flags> -- see <login_class.h> for the 248 * possible values. 249 * 250 * setclasscontext() can only set resources, priority, and umask. 251 */ 252 253 int 254 setclasscontext(const char *classname, unsigned int flags) 255 { 256 int rc; 257 login_cap_t *lc; 258 259 lc = login_getclassbyname(classname, NULL); 260 261 flags &= LOGIN_SETRESOURCES | LOGIN_SETPRIORITY | 262 LOGIN_SETUMASK | LOGIN_SETPATH; 263 264 rc = lc ? setusercontext(lc, NULL, 0, flags) : -1; 265 login_close(lc); 266 return rc; 267 } 268 269 270 271 /* 272 * Private functionw which takes care of processing 273 */ 274 275 static mode_t 276 setlogincontext(login_cap_t *lc, const struct passwd *pwd, 277 mode_t mymask, unsigned long flags) 278 { 279 if (lc) { 280 /* Set resources */ 281 if (flags & LOGIN_SETRESOURCES) 282 setclassresources(lc); 283 /* See if there's a umask override */ 284 if (flags & LOGIN_SETUMASK) 285 mymask = (mode_t)login_getcapnum(lc, "umask", mymask, mymask); 286 /* Set paths */ 287 if (flags & LOGIN_SETPATH) 288 setclassenvironment(lc, pwd, 1); 289 /* Set environment */ 290 if (flags & LOGIN_SETENV) 291 setclassenvironment(lc, pwd, 0); 292 } 293 return mymask; 294 } 295 296 297 298 /* 299 * setusercontext() 300 * 301 * Given a login class <lc> and a user in <pwd>, with a uid <uid>, 302 * set the context as in setclasscontext(). <flags> controls which 303 * values are set. 304 * 305 * The difference between setclasscontext() and setusercontext() is 306 * that the former sets things up for an already-existing process, 307 * while the latter sets things up from a root context. Such as might 308 * be called from login(1). 309 * 310 */ 311 312 int 313 setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags) 314 { 315 quad_t p; 316 mode_t mymask; 317 login_cap_t *llc = NULL; 318 #ifndef __NETBSD_SYSCALLS 319 struct rtprio rtp; 320 #endif 321 322 if (lc == NULL) { 323 if (pwd != NULL && (lc = login_getpwclass(pwd)) != NULL) 324 llc = lc; /* free this when we're done */ 325 } 326 327 if (flags & LOGIN_SETPATH) 328 pathvars[0].def = uid ? _PATH_DEFPATH : _PATH_STDPATH; 329 330 /* we need a passwd entry to set these */ 331 if (pwd == NULL) 332 flags &= ~(LOGIN_SETGROUP | LOGIN_SETLOGIN); 333 334 /* Set the process priority */ 335 if (flags & LOGIN_SETPRIORITY) { 336 p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI); 337 338 if(p > PRIO_MAX) { 339 #ifndef __NETBSD_SYSCALLS 340 rtp.type = RTP_PRIO_IDLE; 341 rtp.prio = p - PRIO_MAX - 1; 342 p = (rtp.prio > RTP_PRIO_MAX) ? 31 : p; 343 if(rtprio(RTP_SET, 0, &rtp)) 344 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 345 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 346 #endif 347 } else if(p < PRIO_MIN) { 348 #ifndef __NETBSD_SYSCALLS 349 rtp.type = RTP_PRIO_REALTIME; 350 rtp.prio = abs(p - PRIO_MIN + RTP_PRIO_MAX); 351 p = (rtp.prio > RTP_PRIO_MAX) ? 1 : p; 352 if(rtprio(RTP_SET, 0, &rtp)) 353 syslog(LOG_WARNING, "rtprio '%s' (%s): %m", 354 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 355 #endif 356 } else { 357 if (setpriority(PRIO_PROCESS, 0, (int)p) != 0) 358 syslog(LOG_WARNING, "setpriority '%s' (%s): %m", 359 pwd->pw_name, lc ? lc->lc_class : LOGIN_DEFCLASS); 360 } 361 } 362 363 /* Setup the user's group permissions */ 364 if (flags & LOGIN_SETGROUP) { 365 if (setgid(pwd->pw_gid) != 0) { 366 syslog(LOG_ERR, "setgid(%lu): %m", (u_long)pwd->pw_gid); 367 login_close(llc); 368 return -1; 369 } 370 if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) { 371 syslog(LOG_ERR, "initgroups(%s,%lu): %m", pwd->pw_name, 372 (u_long)pwd->pw_gid); 373 login_close(llc); 374 return -1; 375 } 376 } 377 378 /* Set the sessions login */ 379 if ((flags & LOGIN_SETLOGIN) && setlogin(pwd->pw_name) != 0) { 380 syslog(LOG_ERR, "setlogin(%s): %m", pwd->pw_name); 381 login_close(llc); 382 return -1; 383 } 384 385 mymask = (flags & LOGIN_SETUMASK) ? umask(LOGIN_DEFUMASK) : 0; 386 mymask = setlogincontext(lc, pwd, mymask, flags); 387 login_close(llc); 388 389 /* This needs to be done after anything that needs root privs */ 390 if ((flags & LOGIN_SETUSER) && setuid(uid) != 0) { 391 syslog(LOG_ERR, "setuid(%lu): %m", (u_long)uid); 392 return -1; /* Paranoia again */ 393 } 394 395 /* 396 * Now, we repeat some of the above for the user's private entries 397 */ 398 if ((lc = login_getuserclass(pwd)) != NULL) { 399 mymask = setlogincontext(lc, pwd, mymask, flags); 400 login_close(lc); 401 } 402 403 /* Finally, set any umask we've found */ 404 if (flags & LOGIN_SETUMASK) 405 umask(mymask); 406 407 return 0; 408 } 409 410